Movable working chair, particularly for dentists

ABSTRACT

A movable working chair, particularly for dentists, has an operating device working against restoring means and moving the chair when it is loaded from a &#39;&#39;&#39;&#39;moving position&#39;&#39;&#39;&#39; into a &#39;&#39;&#39;&#39;braking position&#39;&#39;&#39;&#39; and moving the chair when it is unloaded from the &#39;&#39;&#39;&#39;braking position&#39;&#39;&#39;&#39; into the &#39;&#39;&#39;&#39;moving position&#39;&#39;&#39;&#39;. The invention is particularly characterized by a stop device released by hand or foot by means of which the operating device can be stopped in the &#39;&#39;&#39;&#39;moving position&#39;&#39;&#39;&#39;.

Umted States Patent 11 1 1 3,917,203 Heubeck et al. Nov. 4, 1975 MOVABLE WORKING CHAIR, 2,625,989 1/1953 Pond et a1 188/5 x PAR FOR DENTISTS 2,780,277 2/1957 Ries et a1. 248/408 0 2,847,057 8/1958 l-lolcombe 188/5 X Inventors: Erich Heubeck, Benshelm; 3,197,227 7/1965 Anselmo 1ss/5 x Ernst-August Behne, Bensheim-Auerbach, both of Germany Primary ExaminerRoy D. Frazier Assistant Examiner-Lawrence J. Staab 73 Ass S Aktl llschaft M h, lgnee 62x23 engese umc Attorney, Agent, 0r Fzrm-V. Alexander Scher [22] Filed: Nov. 13, 1973 [21] Appl. No.: 415,450 ABSTRACT Foreign Application Priority Data A movable working chair, particularly for dentists, has Nov. 16, 1972 Germany 2256336 an operating device working against restoring means and moving the chair when it is loaded from a mov- ['52] US. Cl. 248/158; 188/5; 248/188. 1; ing position into a braking position and moving the 280/4324 chair when it is unloaded from the braking position [51] Int. Cl. F16M 13/00 into the moving position. The invention is particu- [58] Field of Search 188/5; 248/ 188.1, 408, larly characterized by a stop device released by hand 248/409, 158; 297/DIG. 4, 345, 349; 01' foot by means of which the operating device can be 280/4324 stopped in the moving position.

[56] References Cited UNITED STATES PATENTS 3 Claims, 2 Drawing Figures 2,590,382 3/1952 Danielson 188/5 X US. Patent Nov. 4, 1975 MOVABLE WORKING CHAIR, PARTICULARLY FOR DENTISTS This invention relates to a movable working chair, particularly for dentists, having an operating device working against restoring means with which the chair when loaded is movable from a moving position into a braking position and when unloaded is movable from the braking position" into the moving position.

Particularly in medical technology it is often desirable to fix a working chair while it is seated firmly on the floor, the chair being generally movable mostly by rollers. In a known chair of this type this is possible by supporting the chair while providing height adjustment by means of a supporting tube in the pedestal part of the chair, whereby the free end of the supporting tube when unloaded is located at a short distance from the floor. When the seat is loaded the supporting tube is moved downwardly against the action of a spring until its free end lies upon the floor and holds the chair like a brake. When the chair is unloaded the supporting tube is again raised from the floor by the spring. The chair is then again in the moving position in which it can be freely moved upon its rollers.

A drawback of this chair is that the user in order to move the chair must be removed from the seat during the entire movement procedure either entirely or at least to such an extent that the free end of the supporting tube will be raised sufficiently from the floor. Thus this makes it necessary for the user to assume an unsatisfactory body position which will become tiring.

An object of the present invention is to provide a movable chair of the described type which will not have this drawback. The chair of the present invention should, on the one hand, prevent an undesired shifting during seating but, on the other hand should be shiftable from the seating position into another position without it being necessary for the user to raise himself 1 from the seat in the above-described manner.

In the accomplishment of the objectives of the pr'esseated. Contrary to the prior art chair, the user is not required to be raised from the chair into the abovedescribed unsatisfactory body position during the shifting. If according to a further embodiment of the present invention the stop device is so constructed or arranged that the operating device can be also stopped in the braking position, then a further drawback of the prior art device is eliminated, namely, that during seating the chair which is then still in the moving position can possibly slide from its original location and be braked in another undesired location. As a rule this would require a correction in the location of the chair by the above described unsatisfactory body position.

According to a further embodiment of the present invention it is suggested that the stop device be provided with preselecting means by the use of which the stopping and the release of the operating device can be set in advance. The preselecting means can be so constructed that the stopping and the release can be set independently from the position of the chair and the load upon the seat. Then the user has the possibility independently from the present location of the chair in the IN THE DRAWING:

5 FIG. 1 is a diagrammatic perspective view of the movable working chair of the present invention.

FIG. 2 is a section along the line II II of FIG. 1 on a larger scale. 1

FIG. 1 illustrates diagrammatically-a movable working chair with a base I upon which is supported by a spring or similar adjusting device a seat 2 which is movable in height and carries an arm support 3. The height adjusting device is not described further herein since it is unimportant for the present invention. The seat 2 is carried by a supporting tube 4 which is movable vertically in the base 1 and is engaged by returning means. A swinging lever 5 is a part of a device shown in FIG. 2 by means of which two positions can be set, namely a stop position and a release position for an operating device.

FIG. 2 shows details of the support of the tube 4 as well as details of the above-mentioned device and of prevents the chair from shifting (braking position).

Two plastic sleeves 9 and 10 are used to guide the tube 4 in the carrier 7. Upon the supporting tube 4 are fixed a first supporting ring 11 engaged by a pressure spring 12 and a second supporting ring 13 which engages a notched bolt 14. The pressure spring 12 which substantially compensates for the weight of the tube 4 and the seat 2 mounted thereon, is supported in the-carrier 7 by a safety ring 15 and an intermediate disc 16. The parts 4, 8 to 12 and 15, 16 can be described as the operating device by means of which the chair can be brought from a moving position into a braking position and vice versa. With the device described hereinafter the operating device can be stopped in the moving position.

The device includes a notched bolt 14 which is supported in a bearing holder 17 so as to be shiftable radially to the tube 4. The bolt 14 has a recess 27 wherein a pressure pin 18 is movably mounted. The pin 18 is supported by a pressure spring 19 against the bolt 14. The pin 18 engages an excenter disc 21 which is adjustable by a shaft 21 mounted in the support 7 and carrying the swinging lever 5. A pin 22 is carried by the excenter disc 20; upon that pin hangs a draw spring 23 serving as the return element for the excenter disc 20. A nut 24 is screwed upon the bolt 14 and has a front surface engaged by a further pressure spring 25 which is supported by an inner 'side of the bearing holder 17. The notched bolt 14 is generally round but has a slightly inclined front side engaged by the tube 4. Its outer surface has a notch 28 upon which the ring 13 is supported.

In the position shown in FIG. 2 the brake bumper 8 is raised from the supporting surface or floor 26. The swinging lever 5 is located in the stop position. The excenter disc 20 presses the pin 18 as far as possible into the recess 27 of the bolt 14. In this position the spring 19 is compressed to the greatest possible extent. The

result is that the bolt 14 is pressed against the outer surface of the tube 4. The nut 24 can be used to change the spring force of the spring 25 acting against the spring 19. Thus the pressure force of the bolt 14 against the tube 4 can be changed.

By the engagement of the lower edge of the bolt 14 with the ring 13 the tube 4 and thus the seat are stopped from a downward movement. The chair is thus located in a locked moving position. If the lever is swung it will be moved into the unlocking position. The pin 18 will be pressed by the spring 19 out of the recess 27. Furthermore the spring acting through the nut 27 upon the bolt 14, will move it so far from the tube 4 that the front edge of the bolt 14 will lie outside of the moving range of the ring 13. When the seat 2 is loaded the tube 4 can move downwardly to such an extent that the brake bumper 8 will press firmly against the floor 26 (braking position). When load upon the seat is removed the springloaded tube 4 will move automatically upwardly into the moving position.

With the swinging lever 5 it is possible to select in advance the positions stop and release independently from the load on the chair and independently from the position in which the chair is then located. If for example, the position stop is selected during seating, namely, when the chair is loaded, the bolt 14 is pressed toward the supporting tube. Then a short weight discharge of the seat (without raising from the seat) is sufficient to permit the ring 13 to slide over the edge of the spring engaged bolt 14. When the seat is loaded the lower side of the ring 13 lies again at the notch 28 of the bolt 14 and thus prevents the sinking of the supporting tube 4 into the braking position.

According to a further advantageous development of the above-described chair the operating device 4, 8 to 12, 15, 16 can be so constructed that the supporting tube 4 can be stopped by the bolt 14 in addition to the moving position also in the braking position. Then the supporting tube 4 is provided with a further ring which when in the braking position lies against the lower edge of the bolt 14 having no inclined surface.

Thus there are the following possibilities of use:

A. Operating device can be stopped only in the moving position.

1. Seat has no load. Lever 5 is in the position stop. When seat is loaded the chair is held in the moving position and thus is freely movable.

2. Seat has no load. Lever 5 is in the position release. When seat is loaded the chair is moved from the moving position into the braking position. When seat is unloaded the chair moves automatically into the moving position.

3. Seat is loaded. Lever 5 is moved from release to stop. Seat is unloaded for a short time. After renewed loading conditions take place described above under 1.

4. Seat is loaded. Lever 5 is moved from stop to release. Seat is unloaded and after renewed loading conditions take place described above under 2.

B. Operating device can be stopped also in the braking position.

1. Seat is unloaded. Lever 5 is in the stop position. (As use in A.l).

2. Seat is unloaded. Lever 5 is in the release position. (As use in A.2).

3. Seat is loaded. Lever 5 is moved from release to stop. When seat is unloaded it remains in the brakin position.

4. Seat is loaded. Lever 5 is moved from stop to release. (As use in A.4).

The brake bumper 8 is so constructed that it can be 1. A movable working chair, particularly for dentists,

comprising a base having means for rolling the chair along the floor, a seat and a support member carrying said seat, brake means connected to said support member for movement from a release position wherein brake means is spaced from the floor to a braking position wherein the brake means engage the floor in response to loading of said seat, restoring means for moving said brake means from the braking position to the release position in response .to unloading of said seat,

and stop means movable between a retracted and extended position for selectively blocking movement of a said brake means, and stop means in said retracted po-. sition permitting movement of said brake means between said braking and release positions, and in said extended position permitting movement of said brake means only. from said braking position to said release position, said stop members having connected thereto manually operable preselecting means for biasing said stop means into either one of said retracted and extended positions irrespective of the position of said brake means and the seats load.

2. A working chair according to claim 1, wherein said support member comprises a supporting post carried by said base and vertically movable therein, said post having a lower end adapted to engage the floor for.

braking the chair, said stop means comprising a notched bolt extending substantially radially to said post to engage and disengage with said post, a pin slidably engaging said bolt, a first resilient means positioned between said pin and said bolt for urging said bolt into the extended position and a second resilient means positioned between said bolt and said base for urging said bolt into retracted position, said preselecting means having a first setting for enabling said first resilient means to overcome the urging of said second resilient means, whereby said bolt is biased toward said extended position, said preselecting means having a second setting for enabling said second resilient means to overcome the urging of the first resilient means,

whereby said bolt is biased toward said retractable position.

3. A working chair according to claim 2, wherein said preselecting means comprises a swingable lever and an excentrically mounted. disc connected with said lever and having an outer surface engaging said pin for changing the compression of said first resilient means. i V 

1. A movable working chair, particularly for dentists, comprising a base having means for rolling the chair along the floor, a seat and a support member carrying said seat, brake means connected to said support member for movement from a release position wherein brake means is spaced from the floor to a braking position wherein the brake means engage the floor in response to loading of said seat, restoring means for moving said brake means from the braking position to the release position in response to unloading of said seat, and stop means movable between a retracted and extended position for selectively blocking movement of said brake means, and stop means in said retracted position permitting movement of said brake means between said braking and release positions, and in said extended position permitting movement of said brake means only from said braking position to said release position, said stop members having connected thereto manually operable preselecting means for biasing said stop means into either one of said retracted and extended positions irrespective of the position of said brake means and the seat''s load.
 2. A working chair according to claim 1, wherein said support member comprises a supporting post carried by said base and vertically movable therein, said post having a lower end adapted to engage the floor for braking the chair, said stop means comprising a notched bolt extending substantially radially to said post to engage and disengage with said post, a pin slidably engaging said bolt, a first resilient means positioned between said pin and said bolt for urging said bolt into the extended position and a second resilient means positioned between said bolt and said base for urging said bolt into retracted position, said preselecting means having a first setting for enabling said first resilient means to overcome the urging of said second resilient means, whereby said bolt is biased toward said extended position, said preselecting means having a second setting for enabling said second resilient means to overcome the urging of the first resilient means, whereby said bolt is biased toward said retractable position.
 3. A working chair according to claim 2, wherein said preselecting means comprises a swingable lever and an excentrically mounted disc connected with said lever and having an outer surface engaging said pin for changing the compression of said first resilient means. 